The dub was very very good. Crispin Freeman as usual was flawless with Kyon's voicing. In regards of Alt!Yuki's voice...I actually liked it. The thing is for me, in the Japanese dub, I found Yuki's moe voice annoying. In this dub, it suits her bookworm persona more than the moe aspect. (And I dislike moe) I actually felt sympathy for Alt!Yuki in the english dub in the sense her voice was less annoying to me.